/*
 * whoisclient.c - main 
 * from Doug Comer Internetworking with TCP/IP vol. 1 pp. 357
 */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#define bcopy(a,b,c) strncpy(b,a,c)

/* --------------------------------------------------------------
 * Prgram  :   whoisclient
 * Purpose :   UNIX application program that becomes a client
 *             for the Inetnet "whois" service.
 * Use     :   whois hostname username
 * Author  :   Barry Shein, Boston University
 * Date    :   January, 1987
 *
 * Modification : Since the original program requires super-user
 *                privilege we modify the program to use a
 *                non-privilege port so every one can execute it.
 *                We use port 2500 (randomly chosen).
 *                By Xiannong Meng, Bucknell University, 1/16/93
 *--------------------------------------------------------------
 */

#define WHOISPORT     2500 /* a non-privilege port so all can use */

main(argc,argv)
int argc;
char *argv[];               /* C command line arguments         */
{
   int s;                   /* socket descriptor                */
   int len;                 /* length of received data          */
   struct sockaddr_in  sa;  /* socket addr. structure           */
   struct hostent * hp;     /* host entry                       */
   struct servent * sp;     /* service entry                    */
   char buf[BUFSIZ + 1];    /* buffer to read whois info        */
   char *myname;            /* pointer to name of this program  */
   char *host;              /* pointer to remote host name      */
   char *user;              /* pointer to remote user name      */

   myname = argv[0];

   /*
    * Check that there are two command line arguments
    */
   if (argc != 3)
   {
       fprintf(stderr, "Usage: %s host username\n",myname);
       exit(1);
   }

   host = argv[1];
   user = argv[2];

   /* 
    * Look up the specified hostname
    */
   if ((hp = gethostbyname(host)) == NULL)
   {
       fprintf(stderr, "%s: %s: no such host?\n",myname,host);
       exit(1);
   }

   /*
    * Put host's address and address type into socket structure
    */
   bcopy((char *)hp->h_addr, (char *)&sa.sin_addr, hp->h_length);
   sa.sin_family = hp->h_addrtype;
   
   /*
    * Put the whois socket number into the socket structure.
    */
   sa.sin_port = WHOISPORT;

   /*
    * Allocate an open socket.
    */
   if ((s = socket(hp->h_addrtype, SOCK_STREAM, 0)) < 0)
   {
      perror("socket");
      exit(1);
   }

   /*
    * Connect to the remote server.
    */
   if (connect(s,(struct sockaddr *)(&sa),sizeof sa) < 0)
   {
      perror("connect");
      exit(1);
   }

   /* 
    * Send the request
    */
   if (write(s,user,strlen(user)) != strlen(user))
   {
      perror("write");
      exit(1);
   }

   /*
    * Read the reply and put to user's output
    */
   while ( (len = read(s,buf,BUFSIZ)) > 0)
      write(1,buf,len);
   close(s);
   exit(0);
}